Have you ever wondered how diplomatic immunity works? Well, prepare to know!
The concept of people who speak on behalf of a leader or state being untouchable is a very ancient one, and probably dates back around the first time a situation required it, when there was more than one civilization. The second-millennium BC Babylonian ruler and first lawgiver, Hammurabi, was recorded as having violated the spirit of diplomatic immunity by refusing to provide safe passage for the return trip of foreign envoys that had brought him a message he didn't like. This means that by as late as 4,000 years ago, the concept of diplomatic immunity was already established.
Over the millennia it hasn't changed too terribly much. Great thinkers such as Cicero and Machiavelli helped smooth out its rough points. Its customs have been set in stone through precedent created by interactions between such huge statesmen as Peter the Great and Queen Elizabeth I. Thomas Jefferson disdained the concept of diplomatic immunity, taking the French Revolution's view that it was simply implicit agreements among nations to allow spies and subversives within one another's borders. This was ironic because he was the U.S. ambassador to France around that time.
Overall, diplomatic immunity hasn't changed much over the years. It's based mostly on two principles, the most recent of which was created back at the beginning of the Renaissance era. The first principle - the oldest one, which Hammurabi broke - is personal inviolability. This concept says essentially that diplomats are untouchable. Since this idea is only as strong as a host state's willingness to observe it, some cultures have added an extra layer of divine protection to the diplomat's status. The ancient Greeks considered diplomats as representatives of Zeus, and the Pope's nuncii were considered holy emissaries, being that they were dispatched by the Pope.
For the most part, however, a diplomat's personal inviolability springs from reciprocation - you don't kill my envoys, I won't kill yours. Since that works the other way equally well - if I kill your guys, you're going to kill mine - reciprocation has more often than not been enough to maintain inviolability among envoys. Genghis Khan, who was a surprisingly progressive ruler, so valued the concept of the inviolability of diplomats that any offending nation would find holy hell rained down upon them were they to kill any of his emissaries. Conversely, the Persian ruler Darius I declined to kill a pair of Spartan nobles he had on hand after Spartan leaders killed two Persian envoys when they arrived with a proposal the Spartans surrender to Darius (as seen in the film The 300). Darius said that such retribution would "wreak havoc of all human law"; his view has over the ages been the predominant one. During the Middle Ages in Europe, after the power vacuum left by the fall or Rome and before the Church establishing the dominance of the Holy Roman Empire, the extent of the power of European kings was uncertain. Yet during this time, the protections and rights of the diplomat were firmly established and in some cases it would have been a greater crime to kill an emissary than a king.
Why should diplomats be afforded such unusually benign treatment? This question has been asked and answered over the centuries. Diplomats, everyone has come to agree, are meant to be emissaries of peace. A diplomat's job is to either bring or maintain peace between two nations and as such the people who carry out this special and important job should be afforded special and important protection. (Remember, I said theoretically. While modern diplomats are still tasked with maintaining peace, the Jeffersonian view of their craft has become much more apparently correct over the years.) Also, being brokers of peace, diplomacy is often part of a last-ditch attempt to avoid war between the diplomat's home country and the host country the diplomat is visiting. If those negotiations break down and war is not averted, the diplomats require safe passage out of the host nation before hostilities begin.
Not only does personal inviolability call for the host nation to refrain from killing or detaining an emissary who brings an unpopular proposal, it also became a call upon host states to protect visiting diplomats from harm from others, including their own people. You can still see this ancient custom still observed today in the form of the NYPD providing escorts to dignitaries visiting the U.N. and in the outcry over the death of the U.S. ambassador to Libya, Christopher Stevens, during an attack on the American embassy in Benghazi. The acting Libyan government, under the customs and norms of diplomatic immunity, had an obligation to protect the American emissaries.
The second main principle that creates modern diplomatic immunity is a bit of legal fiction called extraterritoriality. Legal fictions are concepts that exist in flagrant contradiction to reality but are observed as real for the purposes of expediting legal matters. Corporations are viewed under the law as people, and this is a legal fiction. And, under the law, a person who renounces an inheritance is considered during the will's execution to have died prior to the actually deceased person whose estate is being distributed. Extraterritoriality falls under this umbrella by extending a nation's sovereign soil into the host nation's borders. Embassies and the homes, offices and cars of people with diplomatic immunity are considered to be situated on the soil of the home country. This means that the local police have as little right to invade a diplomat's car or house as they would if the car or house were actually on the home country's soil. For the purpose of the law, they are.
Both of these concepts are illustrated in an international incident in 1708. A Russian diplomat was on his way back to his home country when he was arrested and held at a pub where he'd racked up a substantial debt. No less than Peter the Great requested of no less than Queen Elizabeth I that the envoy be let go. The queen complied and the men who held, quite legally at the time, the diplomat for his indebtedness were punished. Shortly after, England passed an act that said foreign emissaries were exempt from the jurisdiction of the law and were not to be arrested. So in this you have not only personal inviolability and extraterritoriality, you also have a clear illustration of a problem that has long plagued diplomacy and continues to this day: corruption.
When you remove the threat of the possibility of prosecution for crimes in a foreign land and then send that person to the foreign land, you create an extremely tantalizing situation. In theory, a person with diplomatic immunity is still under the jurisdiction of their home land's laws and in some cases, emissaries who have broken the law in a host country are tried in their home countries for the crime. In practice, though, people with diplomatic immunity exist in a lawless state. Technically they can be arrested and detained for a crime, but under diplomatic immunity the courts of the host county have no jurisdiction to prosecute them and so charges would inevitably be dropped. (This still today includes the accrual of debts, just as with the 18th-century Russian diplomat in England and diplomats often have trouble establishing lines of credit in host countries because lenders would have no way to collect on any default.) As a result, there is an international calculus that nations carry out to arrive at what will be done with a person with diplomatic immunity who commits a crime. If the crime is negligible enough, the host country generally looks the other way. As a result, in July 2011 the city of New York was owed $16.7 million in unpaid traffic and parking tickets by people with diplomatic immunity.
Remarkably, most people with diplomatic immunity tend to observe the laws of the host country, as is required of them by the UN Geneva Convention on Diplomatic Immunity of 1961, which codified the longstanding customs surrounding the concept. There are cases - and they tend to be sensationalized when they occur, due, one imagines, to the public fascination with the idea that there are people out there who legally exist outside of the law - where people with diplomatic immunity have failed to observe this honor system. Most frequently, people with diplomatic immunity are caught speeding, driving impaired (at times killing others on the road) and engaging in what amounts to human trafficking, a practice that has received increasing scrutiny in recent years thanks to a couple of high profile egregious cases. Remember that the homes of people with diplomatic immunity are considered to be technically situated on foreign soil and so are outside of the reach of American labor laws. For some emissaries, this means bringing domestic servants from their home countries to work in their homes under conditions that are tantamount to slave labor.
When a diplomat violates a law that is serious enough to warrant the host country's attention, those situations themselves often call for some diplomacy. Under the rules of diplomatic immunity, a host country can declare a visiting emissary persona non grata (an unwelcome person) and demand the emissary be recalled. When defense contractor Raymond Davis killed two would-be assassins in Lahore, Pakistan in 2011 he created an international incident that strained the limits of the already shaky diplomacy between the U.S. and Pakistan. Though not technically a diplomat, Davis had entered Pakistan on a diplomatic passport which, under international law, meant that Pakistan admitted him to their country with diplomatic immunity. In the aftermath of the shooting, American diplomats brokered a deal to maintain relations between the two countries. Davis was removed from Pakistan, as would have been customary and necessary, but Pakistan also secured the removal of other diplomats it suspected were engaged in spying and other intelligence and defense activities in the nation's borders. Pakistan handed over a list of 331 Americans working in Pakistan with diplomatic immunity who they wanted recalled to the U.S. The Pakistanis stopped just short of declaring the emissaries personae non grata, which, after a declared period of time they would be granted to leave the country and never return, their diplomatic immunity would cease and they would be liable for prosecution in the host country. The host country need not give a reason for declaring an individual persona non grata and, although it's a big deal when they do, some host countries use the tactic as a means of expelling diplomats who are publicly critical of the ruling regime.
In cases where it's deemed politically wise, a diplomat's home country can also waive an emissary's diplomatic immunity; this would make the emissary subject to the jurisdiction of the host country and would put them in fairly hot water, their home country having turned their back on them and their host nation likely out for blood in return for the crime they committed. An emissary cannot waive their own immunity, however.
When the UN created the 1961 convention on diplomatic immunity set into international law customs and traditions that stretched back millennia but it did so in the context of a world that was very much changed from the one that necessarily gave rise to those original customs and traditions. Protections that were created to prevent the finality of an emissary's beheading at the hands of an angered foreign ruler or besiegement at the hands of bandits during the weeks-long trip back home no longer apply and yet the same protection is still afforded to those with diplomatic immunity. These customs were created a time before the leadership of a nation was itself subject to prosecution. As governments and government officials are now liable to lawsuits, the need to protect diplomats from their once-unquestioned actions has fallen away. Yet while world governments have modernized, the protections for diplomats remain the same and have been expanded even. After the First and Second World Wars, non-state actors, international organizations that have no borders, became increasingly powerful and necessary to things like trade and aid and came to also be granted diplomatic immunity. Over the decades, this led to something of a run on diplomatic immunity, the blanket statuses of inviolability and extraterritoriality being granted far and wide to members of groups like the Inter-American Tropical Tuna Commission. And, under the UN convention, this includes the immediate family members and domestic staff of the members of the Inter-American Tropical Tuna Commission.
You can see how all of this has created something of a mess of diplomatic immunity. Some in the diplomatic community have called for the exercise of a third principle, functional necessity, which dictates that the aspects of diplomatic immunity granted to an emissary only go so far as their diplomatic mission requires. Sure, diplomats require a minimum of immunity from legal harassment, but they should probably still have to pay their parking tickets.
Although functional necessity is part of the framework of the 1961 Vienna Convention on Diplomatic Immunity, it is the least likely to be followed. The same current framework that grants immunity for a diplomat's teenage son from prosecution for drunk driving also allows for tacitly agreed-upon spycraft around the world. And although the U.N. has the power to push for changes that limit the scope of diplomatic immunities, it too is as entrenched in the current model as anyone else: As recently as 2010, the U.N. cited diplomatic immunity to protect itself following a cholera outbreak that killed 8,000 Haitians when a group of Nepalese soldiers who hadn't been tested for the disease were deployed to the country to provide aid following the massive earthquake there.
And that's everything I know about diplomatic immunity.